Fluid testing and fluid sampling apparatus and methods are known in the prior art and have been used for many years. Although fluid testing apparatus such as disclosed in U.S. Pat. No. 2,396,470 may suffice for the purpose of testing a sample of a liquid, such fluid testing apparatus is awkward and is difficult to use for obtaining and containing a sample of a liquid.
Some prior art fluid sampling devices, such as a syringe, have had the disadvantage of requiring visual monitoring and direct control and handling while obtaining the sample, which is undesirable for many applications. Examples of such applications include taking submersed samples from a volume of liquid, and sampling where operator proximity to the sampled liquid should be minimized as in sampling hazardous liquids.
Other sampling devices comprising elastomeric valve materials such as rubber may not sufficiently withstand corrosive or other hostile liquid environments, which severely limits the range of applications of such devices. Another problem with some prior art sampling devices is that they may require pumping the sample to a transport container instead of retaining the sample within the sampling chamber, which may be undesirable in some applications. For example, in sampling a two-phase system such as a photographic emulsion it is desirable to obtain the sample with the phases representative and unchanged or undisturbed by such pumping and transport operations.
There are many situations where it is desired to sample a fluid at a predetermined depth, but with prior art sampling devices it can be difficult to control and verify at what depth the sample is being drawn. Thus, the operator may not be able to adjust the sampling apparatus to accommodate various sampled liquids, sampling depths, and sampling time. Another problem is that the sample can tend to leak out of the sampling container.
Still another problem with known sampling devices and methods is that they may allow the drawing of one discreet sample but not be conducive to the concurrent drawing of multiple samples by one operator or by one operation or step. For example, it may be desirable to obtain concurrent samples to determine, for example, whether a liquid is well-mixed or stratified. Such sampling devices and methods may also not allow the operator to control the rate at which a sample is drawn or the volume of sample obtained. Such liquid samplers may also not be convenient to use in obtaining multiple samples in a dark environment, for example as is necessary in photographic manufacturing processes.